Question

At 8:00 AM a bicyclist departed city A, heading towards city B at a rate of 20 km/h. After traveling for 4 hours he stopped for an hour break. At the same time, a biker left city A traveling in the same direction at the rate of 50 km/h. How long will it take the biker to catch up to the cyclist?

Answer 1

2 hrs

Explanation:

after 4 hours the first biker went 80 miles (4 hours*speed(20kph))

when the first biker sat down to take a break the second one started, after one hour the second biker has went 50 kilos and the first biker nothing (because of the break).

so now the distance between them is 30 miles because the first one went 80 kilos, and the second went 50, so 80-50=30 so now they have 30kilos between them and scine the diffrence in the speed is 30 and they have 30 apart then just one more hour, and now 1 hour +1 hours=2 hours

Answer 2

2 hours and 40 minutes

Explanation:

After 4 hours, 1st person went 20 * 4 = 80 km

+1 hours rest

So now after total 5 hours (when 2nd one started), 1st one is 80 km ahead.

2nd bicyclist rate is 50

1st bicyclist rate is 20

So, for each hour, 2nd bicyclist advances 50 - 20 = 30 kilometers

How long will it take him, at this rate, to catch up 80 kilometers??

Simple!

30 km catch up every hour, so

80/30 = 2 2/3rd hours

That would be 2 hours 40 minutes to catch up